This invention relates generally to radio frequency antennas and more particularly to radio frequency antennas adapted to operate at relatively high power levels and provide antenna patterns having relatively low sidelobes over a relatively wide band of frequencies.
As is known in the art, low sidelobe antennas have a wide range of application. One such antenna suggested to provide low sidelobe antenna patterns is discussed in an article entitled "A Parabolic Cylinder Antenna With Very Low Sidelobes" by Fanti, Franchi, Kernweis and Dennett published in IEEE Transactions on Antennas and Propagation, Vol. AP-28 No. 1, January 1980 pages 53-59. Here a hog horn reflector antenna is excited by a single, large aperture feed which provides its phase and amplitude distribution for the hog horn by generating multiple modes of propagation from the single feed. Since, for the proper amplitude and phase distribution, it is necessary to generate these multiple modes of propagation and because these power multiple modes of propagation are generated at only a single frequency, or a relatively narrow band of frequencies, such antenna is not useful in applications requiring a relatively large frequency bandwidth. Further, the feed of such antenna is relatively complex to fabricate and the antenna is relatively large in size thereby further limiting its application.